Examination of a physically based, high-resolution, distributed Arctic temperature-index melt model, on Midtre Lovénbreen, Svalbard

first_imgImprovements in our ability to model runoff from glaciers remain an important scientific goal. This paper describes a new temperature-radiation-index glacier melt model specifically enhanced for use in High-Arctic environments, utilising high temporal and spatial resolution datasets while retaining relatively modest data requirements. The model employs several physically constrained parameters and was tuned using a lidar-derived surface elevation model of Midtre Lovénbreen, meteorological data from sites spanning ~70% of the glacier’s area-altitude distribution and periodic ablation surveys during the 2005 melt season. The model explained 80% of the variance in observed ablation across the glacier, an improvement of ~40% on a simplified energy balance model (EBM), yet equivalent to the performance of a full EBM employed at the same location. Model performance was assessed further by comparing potential and measured runoff from the catchment and through application to an earlier (2004) melt season. The additive model form and consideration of a priori parameters for the Arctic locality were shown to be beneficial, with a planimetry correction eliminating systematic errors in potential runoff. Further parameterisations defining modelled incident radiation failed to yield significant improvements to model output. Our results suggest that such enhanced melt models may perform well for singular melt seasons, yet are highly sensitive to the choice of lapse rates, and their transferability to different locations and seasons may be limited. While modelling ablation requires detailed consideration of the transition between snow and ice melt, our study suggests that description of the ratio between radiative and turbulent heat fluxes may provide a useful step towards dynamic parameterisation of melt factors in temperature-index models.last_img read more

HMS Diamond Joins Australian Warship East of Suez

first_imgHMS Diamond has taken her place among the international naval effort determined to stamp out criminal activity on the seas east of Suez. The state-of-the-art destroyer has relieved her sister HMS Daring as the latest Royal Navy warship serving with the 26-nation Combined Maritime Forces, sailing in tandem with Australia’s HMAS Melbourne.Admittedly, HMAS Melbourne rather than the antipodean metropolis, but it’s a start.Indeed the link-up with the Adelaide-class frigate east of Suez was the perfect introduction for the Portsmouth-based destroyer to her new mission.Diamond has now joined the Combined Maritime Forces – the partnership of more than two dozen navies committed to keeping the seas clear of all manner of nefarious activity (pirates, smugglers, drug-runners, people traffickers, terrorists) – which will oversee many of her activities for the next four or five months.The Bahrain-based forces directs the work of three distinct task groups of around half a dozen warships each, operating from the head of the Gulf to the Red Sea in the west, shores of India and Pakistan in the east and Seychelles in the south – an area of some 2½ million square miles or more than eight times the size of the North Sea.The ships allocated to those three task forces – 150 (counter-terrorism/maritime security), 151 (counter-piracy), 152 (maritime security in the Gulf) – typically operate as ‘lone wolves’, hundreds of miles away from other vessels assigned to the same force.So the rare link-up between Diamond and Melbourne allowed for a series of drills, manoeuvres and the obligatory ‘photo exercise’ for the record.Diamond has just relieved her older sister Daring on station east of Suez (D32 is making her way back to Portsmouth through the Med presently) as she knuckles down to her maiden deployment; she’s now engrossed with counter-terrorism and piracy patrols, bringing security and stability to the region.“We have a vital role to play in keeping these sea lanes safe for international trade, not just for the UK but for the good of the wider global economy,” explained her Commanding Officer Cdr Ian Clarke.“It is a massive and important task and we are looking forward to working with colleagues from 26 navies including Australia, Pakistan, South Korea and Thailand as well as our US and European partners.” His ship and the 200 sailors, Lynx crew and Royal Marines aboard will continue their patrol of these waters until their expected return home in late December.[mappress]Naval Today Staff, July 20, 2012; Image: Royal Navy View post tag: Diamond View post tag: Suez Share this article View post tag: joins View post tag: Warship View post tag: Australian View post tag: Navy July 20, 2012center_img HMS Diamond Joins Australian Warship East of Suez Back to overview,Home naval-today HMS Diamond Joins Australian Warship East of Suez View post tag: East View post tag: News by topic View post tag: Naval Training & Education View post tag: HMSlast_img read more

Powell: Di Canio appointment ‘bold’ move

first_img That was when denying he has any racist tendencies. Powell is black. Asked about Di Canio’s political views after Charlton’s draw with Brighton in the npower Championship on Tuesday night, Powell said: “You will have to ask him.” When asked how he thought Di Canio would do at Sunderland, Powell said: “The proof will be their remaining games. He has done well so far in League One and Two with Swindon.” Powell added: “Paolo was part of my club career, being a team-mate of mine and I met him socially. “Sunderland has made a bold decision.” There has been a strong reaction on Wearside and further afield to Di Canio’s appointment as manager of the Barclays Premier League strugglers, because of the past comments and actions of the former West Ham, Sheffield Wednesday, Charlton and Lazio striker. Di Canio has refused to expand on a 2005 interview with an Italian news agency when he said he was “a fascist, but not a racist”. Powell said: “It’s remarkable it didn’t come out when he was manager of Swindon. It’s a bold gamble football-wise.” Black Cats head coach Di Canio refused to confirm or deny whether he is a fascist in a press conference on Tuesday and labelled the furore over his appointment as Sunderland manager “ridiculous and pathetic”. The 44-year-old Italian named former Charlton left-back Powell, now manager of the Addicks, as one of his best friends from his playing days in English football when he issued a statement on Monday. Paolo Di Canio’s former team-mate Chris Powell believes Sunderland made “a bold decision” in appointing the Italian as their new boss.center_img Press Associationlast_img read more